There is a recent resurgence of interest in the use of high Intensity Focused Ultrasound (HIFU) for various therapeutic applications. Although HIFU technology has been considered for therapy for over 40 years, it is only recently that advances in computer and transducer technology has permitted its serious consideration for use in clinical practice. The development of the Sonablate(TM) 200 by Focus Surgery, Inc. for the treatment of Benign Prostatic Hyperplasia (BPH) has been a novel example of this technological advancement. This device, currently in clinical use in Asia and Europe and under trials in the US, uses a transrectal ultrasound (TRUS) probe for prostate imaging and the same probe for HIFU to produce lesions in the prostate. The probe combines ultrasound imaging technology with HIFU, and represents a unique and innovative approach to non-invasive surgery. Indeed, between the lesion is produced principally via a local temperature increase, coagulative necrosis is induced, and no bleeding is associated with this surgery. This proposal address a specific technological advance required in order to expand the treatment beyond BPH and to apply this technique to the condition of localized prostate cancer, as well as other treatment of minimally invasive surgery. Specifically, it is proposed to use some recent experimental data obtained on the acoustic attenuation for various tissue, at various temperatures to develop a ultrasound technique for imaging and monitoring of the lesion in a non-invasive manner. During Phase I, we propose to develop real-time computer software to control therapy dosage. This will be based on tissue temperature monitoring by computing acoustic attenuation from the backscattered ultrasound signals during the therapy process. We anticipate that when these goals are achieved in the Phase I study, an immediate extension to animal and human trials would be undertaken in Phase II by modifying the Sonablate(TM) 200 with this new software and hardware to control and monitor therapy process more precisely. PROPOSED COMMERCIAL APPLICATION: BPH and prostate cancer are becoming ever-more-frequent maladies for modern man. The longer a man lives, the more likely it is that we will need to be treated for BPH or prostate cancer. This company currently manufactures such a system for the treatment of BPH. However, an important limitation of this system is it inability to image the lesion produced by the device. A successful completion of this project opens a path toward the expansion of the market for our device for the treatment of prostate cancer.